Abstract: A keyboard which has 10 keys controlled by the four fingers and four keys controlled by the thumb of the same hand. On it, the operator forms chords somewhat as a pianist forms chords on a piano. It allows the user to type at normal speed using only one hand and offers the possibility of typing at a faster rate than the conventional two-handed keyboard. The operator presses several keys at once, as when playing a chord on a piano. Each finger or thumb can press one key, or overlap two or four adjacent keys to press the two or four keys. There are 27 such finger positions on the 10 finger keys and 7 thumb positions on the four thumb keys. The thumb position on the thumb keys select the alphabet/case, output order of characters in the chord, a space character preceding the chord, and capitalizing of the first outputted character of a chord. The finger positions on the finger keys select the characters in the alphabet/case selected by the thumb position.